There is increasing concern about inert ingredients in pesticide formulations, which may themselves be toxic. Consider this article from Beyond Pesticides.
Former Undisclosed Ingredients in Pesticides Products Found in Fish, Birds, and Dolphins
Chemicals previously used as inert ingredients in pesticide formulations have been detected in a wide range of North American wildlife species, according to research published in the journal Environmental Science and Technology. The compounds, perfluroalkyl phosphinic acids (PFPIAs), were widely used as anti-foaming agents in pesticide formulations until 2006, when the U.S. Environmental Protection Agency took regulatory action to cancel their use, citing “human health and environmental risks of concern.” However, the chemicals continue to be used today in consumer goods, including carpet cleaning formulas.
While scientists did not find what they would consider high concentrations of the chemicals in wildlife, the ubiquity of the detections was found to be most concerning. Researchers detected the presence of PFPIAs in the blood of 100% of animals sampled. This includes northern pike in Montreal, Canada, cormorants from the Great Lakes, and bottlenose dolphins from Sarasota Bay, Florida. “We aimed for diversity: air-breathing versus water-breathing, differences in habitat, different taxonomic groups,” Amila O. De Silva, PhD, coauthor of the study, said to CNN. Part of the reason for the wide range of detection lies with the properties of these chemicals. They are highly stable and resist degradation from exposure to water or sunlight, or breakdown by microbes. Dr. De Silva indicated to CNN that the usual ways that the environment remediates chemicals “don’t seem to apply” to PFPIAs....
Beyond Pesticides. 2016. Former undisclosed ingredients in pesticides products found in fish, Birds, and Dolphins. Available from http://beyondpesticides.org/dailynewsblog/2016/10/former-inert-ingredient-pesticide-products-found-fish-birds-dolphins/